The application offers you to test your ability to count in your mind. Great for children. The test consists of 20 examples, 5 examples of addition, subtraction, multiplication and division, which must be performed on time. In case of an error, an additional example is given. Your best time is recorded and saved. The test consists of 4 difficulty levels (for now). If you have your wishes and you like the application, we will prepare more difficult levels.